Private companies in the UK pay around 28% tax on profits, compared to 50% income tax for individuals earning over £150,000 a year. Expenses such as travel, clothing and make-up also become tax-deductible.

They have also changed their registered addresses to Irish accountancy firm Live Wire Business Management, which helps clients be more tax efficient. Ronan Keating, The Cranberries, Girls Aloud and Westlife have used the firm in the past.

"The lads are about to get a huge cash windfall after a year in the music business," a source told The Sun.

"They are on course to become very wealthy young men indeed. They have been given wise advice to move their business address abroad to be as tax efficient as possible.

"It looks like they are on the road to superstardom in the US too - so they will need to be wise about how they handle their earnings."